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Dec. 20, 1966 B. B. TlPPIN ET AL DECIMAL POINT COVERS Filed Jan. 18. 1965 PIE 1 PIE 4 FIE El INVENTORS WALTER E U FF BY BILLY a. T/PP/N fin. AGENT United States Patent 3,292,851 DECIMAL POINT COVERS Billy B. Tippin, Orangeburg, S.C., and Walter Rufi, West Seneca, N.Y., assignors to SCM Corporation, New York, N.Y., a corporation of New York Filed Jan. 18, 1965, Ser. No. 426,252 1 Claim. (Cl. 235-61) The invention pertains to indicia covers for office business machines or the like and is related more particularly to slidable covers for covering and uncovering decimal point indicators on the faceplate of a calculating machine.

The present invention is an improvement of molded plastic decimal point covers which are disclosed in US. patent application, Serial Number 227,142, filed October 1, 1962, now Patent No. 3,185,533.

Each decimal point cover of the aforementioned patent application comprises rearward extending tabs which are inserted into individual slots in a faceplate mounted on a shiftable carriage of a calculating machine. The slots in the faceplate are elongated to permit lateral sliding of the covers to cover and uncover adjacent decimal point indicators painted on the faceplate. In practice it is found necessary to maintain close tolerances in the molding of the plastic decimal point covers in order for them to fit loose enough to permit movement withrespect to the faceplate yet tight enough to maintain their positions despite movements of the carriage. The close tolerances are also required to fit the covers tight enough in the slots to prevent their accidental removal from the faceplate.

Accordingly, a general object of the invention is to provide manually movable indicia cover-s which are maintained in the positions to which they are moved.

Another object is to provide an arrangement of indicia covers in which the covers may be manufactured within wide tolerances and then mounted on a shiftable carriage of a calculating machine so that shifting movement of the carriage will not disturb the setting of the covers.

Another object is to lock indicia covers in their mountings for slidable engagement therewith by simplified common means.

Other objects and advantages of the invention will appear from the following description, reference being had to the accompanying drawing, in which:

FIG. 1 is a front view of a calculating machine carriage faceplate equipped with decimal point indicators and covers therefor.

FIG. 2 is an enlarged perspective view of a decimal point cover for mounting in a calculating machine carriage faceplate.

FIG. 3 is an enlarged top view, partially in section, of the carriage faceplate of FIG. 1 showing two decimal point covers mounted therein, one in position to display the associated decimal indicator and the other in position to conceal the associated decimal point indicator.

FIG. 4 is an enlarged right side view, partially in section, of the faceplate showing a decimal point cover mounted therein.

Decimal point covers 9 (FIG. 1) are mounted on a faceplate 11 which may be secured to a calculating machine carriage which is transversely shiftable in a conventional manner. The faceplate is provided with openings or windows 13 through which numeral wheels mounted in the carriage may be displayed. Decimal point indicia of indicators 15 are painted on the faceplate 11 to the left of each window 13. The color of the decimal points contrast with the color of the faceplate, while the color of the covers 9 preferably matches the faceplate. The decimal point covers are mounted in lateral slots 17 for manual movement leftward and rightward to selectively display one or more decimal points.

The decimal point covers 9 preferably are molded of a resilient material such as polypropylene plastic in the form shown in FIG. 2 and are easily assembled into the faceplate 11. Two tabs 19 extend from the rear of each cover 9 and are molded integrally therewith. A space 18 between the tabs provides flexibility of the tabs inwardly. A small projecting surface 21 is provided on either side of the tabs 19 for sliding engagement with the faceplate 11. The surfaces 21 hold the main portion of the cover 9 away from the faceplate, thereby preventing defacement of the associated decimal point.

During assembly of a decimal point cover, angled portions 20 of the tabs 19 are engaged with the lateral sides of a slot 17 and then pushed through the slot. The space between the tabs allows the tabs to be forced inwardly and then to spring outwardly to slidably engage the sides of the slot. The length of each slot 17 is great enough that respective covers 9 may be moved endwise to cover and uncover selected decimal points 15.

A feature of the invention and the departure from the aforementioned patent application is the provision of a flexible rod 23 (FIGS. 1, 3 and 4) for each lateral row of covers 9. In practice the rod used is a flexible metal wire. After the covers 9 are inserted into respective slots 17, the rod 23 is forced against the rear of individual tabs 19, driving them outwardly, i.e. sidewise, to permit the rod to seat in recesses or lateral arcuate grooves 25 (FIGS. 2 and 4). As the rod 23 is moved into place in the grooves 25, the tabs 19 flex inwardly to the position shown in FIG. 4, locking the covers from removal from the slot.

In practice it has been found that the rod 23 is very easily engaged and removed from the grooves 25, yet it is held securely in place against the motion of the carriage. Friction between the rod and the covers has been found to be low and thus does not hinder lateral movement of individual covers.

Since the rod 23 holds the tabs 19 outward against any forces which tend to cause inward flexure, a great deal of force is required to remove a cover 9 from the faceplate as long as the rod is in place. Accidental removal of a cover 9 is virtually eliminated by this arrangement.

Another purpose of the rod 23 is to permit manufacture of the tabs 19 of covers 9 within wide tolerances. Since the tabs 19 are held positively by the rod 23 to prevent inward flexure, the thickness of the enlarged portion of the tabs 19 (FIG. 14) may vary within relatively wide tolerances and still be sufliciently thick to prevent removal of the associated cover.

Another advantage of the invention is that the rod 23 forces the base of the tabs 19 into frictional engagement with the sides of the slots 17 to compensate for wear and for variations in tolerance. The frictional forces set up thereby have been found to improve the setting of the covers 9, i.e. the forces are sufficient to uniformly maintain the covers 9 in the positions to which they are set despite movement of the carriage.

The invention claimed is:

In a calculating machine having a shiftable carriage, a faceplate for the carriage having viewing holes therein and decimal point indicators laterally aligned one each located between and below each adjacent pair of viewing holes:

(a) A plurality of slots in said faceplate laterally aligned with said decimal point indicators;

(b) a plurality of molded plastic decimal point covers;

(c) a pair of tabs extending in a spaced relationship from the rear of each of said covers, each of said tabs having an enlarged outer end which is flexible inwardly upon insertion into, one of said slots and then outwardly to bring the enlarged outer end into engagement with the underside of the faceplate;

(d) an arcuate lateral groove formed in the inward portion of each tab; and

(e) a flexible wire laterally positioned behind said faceplate to simultaneously engage the grooves of all of the tabs of all of said covers to hold said tabs outwardly wherein said tabs are held in frictional engagement with the sides of said slots thereby providing an efiicient connection unaffected by shifting movement of said carriage.

References Cited by the Examiner UNITED STATES PATENTS Kees 116-135 Batcheller 200--153 Cusano 235123 Studley 235-1 Petri et al 242 14 X Perrochat 24-213 X Kytta 24211 X Lindberg 23561 X Anderson 24211 X RICHARD B. WILKINSON, Primary Examiner.

15 LOUIS J. CAPOZI, Examiner.

TERRY J. ANDERSON, Assistant Examiner. 

